[英]In standard SQL, how do I select rows such that for each unique value in one column, all of the values in another column are a specified value?
[英]How can I map data in rows into one row such that each column is a unique value in SQL
这建议我进行条件聚合:
select id,
max(case when UniqueId = 1 then 1 end) as UniqueId1,
max(case when UniqueId = 2 then 2 end) as UniqueId2,
max(case when UniqueId = 3 then 3 end) as UniqueId3,
max(case when UniqueId = 1 then column1 end) as UniqueId1Col1,
max(case when UniqueId = 2 then column1 end) as UniqueId2Col1,
max(case when UniqueId = 3 then column1 end) as UniqueId3Col1,
max(case when UniqueId = 1 then column2 end) as UniqueId1Col2,
max(case when UniqueId = 2 then column2 end) as UniqueId2Col2,
max(case when UniqueId = 3 then column2 end) as UniqueId3Col2
from table t
group by id;
万一您的[Unique ID]
不连续,请考虑以下事项:
例
Select *
From (
Select A.ID
,Col = concat('ID',Dense_Rank() over (partition by ID order by [Unique ID] ),' ',B.Item)
,Value = B.Value
From YourTable A
Cross Apply ( values ('Unique' ,concat('',[Unique ID]))
,('Column1',Column1)
,('Column2',Column2)
) B(Item,Value)
) src
Pivot (max(Value) for Col in ( [ID1 Unique] ,[ID2 Unique] ,[ID3 Unique] ,[ID4 Unique] -- Expand as necessary
,[ID1 Column1],[ID2 Column1],[ID3 Column1],[ID4 Column1] -- Expand as necessary
,[ID1 Column2],[ID2 Column2],[ID3 Column2],[ID4 Column2] -- Expand as necessary
)) pvt
返回
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